Common Infections May Increase Risk of First Stroke

THURSDAY, Nov. 12 (HealthDay News) -- Exposure to five common infections potentially linked to atherosclerosis may increase the risk for first stroke, according to the Northern Manhattan Study published online Nov. 9 in the Archives of Neurology.

Mitchell S.V. Elkind, M.D., of Columbia University in New York City, and colleagues followed a cohort of 1,625 ethnically mixed subjects from northern Manhattan (mean age, 68.4 years) for a median of eight years to determine the association between stroke and common infections, including Chlamydia pneumoniae, Helicobacter pylori, cytomegalovirus, and herpes simplex virus (HSV) 1 and 2. Cox proportional hazards models were used to estimate the association of individual positive test results with stroke, which were combined into a weighted index of infectious burden.

The researchers found that each individual positive test for infection was positively associated with stroke risk after adjustment for other risk factors: hazard ratio for cytomegalovirus, 2.19; for HSV 2, 1.59; for HSV 1, 1.35; for C. pneumoniae, 1.30; and for H. pylori, 1.13. The infectious burden weighted index, adjusted for risk factors and demographics, was associated with an increased risk of all strokes (hazard ratio, 1.39).

"In this prospective cohort study, a weighted index of exposure to five common infections previously implicated in atherosclerotic disease was associated with risk of first stroke. Although individually each infection was positively associated with increased stroke risk, none were individually statistically significant," the authors conclude.